snip
┬*┬*┬*┬*┬*┬*┬*┬*┬*┬*┬*┬*┬*┬*┬*┬*┬*┬*┬*┬*┬*┬*┬*┬*┬* ┬*┬*┬*┬*┬*┬*┬*┬*┬*┬*┬*┬*┬*┬*┬*┬*┬*┬*┬*┬*┬*┬*┬*┬*┬* ┬*┬* ... Of course
we will soon see claims that this is all self-interest by Trek,
whose
sole aim is to sell more lights.

Everybody should know that such articles aren't very suited to
foster
sales of their own products but lights in general.

True. But it's a convenient excuse to dismiss the findings of such
article. Even though Trek is not a major supplier of bicycle
lights, you
can already predict the narrative that will spew forth. You saw it
already with the Odense study.

Yep, afterwards the usual denialist stuff roll in.

Any study showing that a little mag-dyno blinky decreased daytime
solo accidents by 27% is suspicious on its face. If that doesn't
raise an eye-brow, you don't have eye-brows.

I think, that as a lawyer, you likely understand that the fact that the
DRL is powered by a magnetic dynamo is irrelevant in terms of its
effectiveness. You probably also understand, unlike some others, that
correlation and causation are not the same thing.

O.K., let's put it this way -- a very low-powered flasher located at
hub height.

I have been saying correlation is not causation all along -- and thus
my comments about the Odense study. They assume that the data
establishes causation -- except when the data doesn't pass the smell
test. Here is the explanation given in the report for the reduction in
solo accidents:

"The self reporting of accidents is on the other hand somewhat
problematic. Prior to the study, it was expected that the bicycle
running lights would reduce the occurrence of multiparty accidents
involving cyclists. The initial results suggest that this is a very
likely outcome, as the accident rate is 45% lower for the treatment
group than for the control group, when all reported accidents are
taken into account, and 61% lower when only accidents with personal
injury is taken into account. The bicycle running lights were,
however, not expected to affect the occurrence of solo accidents, but
the initial results show; having made sure by closer examination of
the accident descriptions that the accidents in question are in fact
solo-accidents, that the accident rates for solo accidents are 24%
(all accidents) and 27% (person injury accidents) lower for the
treatment group than for the control group; the effects close to being
significant.

It is likely that this apparent effect on solo accidents of the
bicycle running lights actually reflect a systematic under-reporting
of accidents in the treatment group due to an inherent bias in favour
of the bicycle running lights amongst the members of the treatment
group. During the project, additional questionnaires were carried out
in order to evaluate the design and functionality of the bicycle
running lights. From the data gathered here, it is evident that the
members of the treatment group were very fond of the running light as
they found the bicycle running lights very convenient, e.g. they did
not have to buy batteries any more, they did not have to fear being
stopped by the police for having forgotten their bicycle lights, they
felt very safe with the bicycle running lights etc. As a consequence
it is likely that the treatment group has been somewhat strategic in
their reporting of accidents by omitting some of the minor bicycle
accidents; as reflected by the apparent under reporting of solo
accidents in the treatment group. The apparent effect for solo
accidents is almost the same for relevant subgroups of solo accidents,
see Table 9, which suggests that the underreporting is general and not
associated with certain solo accident types.

O.K., so could the same light-loving study group be under-reporting
multi-rider accidents?

61% reduction in PI accidents by using a weak hub-height blinky?
Hmmmm. I ride and drive around bikes all the time during the day, and
I've never seen a bike because it had a little Knog light. Not during
the day.

The table doesn't even address vertical angle. I guess the cars are
really low to the ground in Denmark.

You can't know the reason. It's like the famous, oft-misquoted, Thompson
helmet study. Further "meta-analysisÔÇŁ reduced the claimed 85% reduction
to between 25% and 55%. But as one report admitted "Experiments on
people are unethical.┬* So researchers instead collect hospital data on
people involved in bicycle crashes." And left out of this kind of study,
by default, are all cyclists whose helmet mitigated the effect of the
crash to the extent that they never went to the hospital.

So in response to Jay's detailed remarks, you're switching topics to
defend a notorious pro-helmet study that even the federal government now
disowns? Because of a lawsuit threat, the NHTSA was force to admit the
Thompson & Rivara study does not meet the government standards for
accuracy. Almost 30 years of lack of corroboration finally had an effect.

snip
************************************************** * ... Of course
we will soon see claims that this is all self-interest by Trek, whose
sole aim is to sell more lights.

Everybody should know that such articles aren't very suited to foster
sales of their own products but lights in general.

True. But it's a convenient excuse to dismiss the findings of such
article. Even though Trek is not a major supplier of bicycle lights,
you
can already predict the narrative that will spew forth. You saw it
already with the Odense study.

Yep, afterwards the usual denialist stuff roll in.

Any study showing that a little mag-dyno blinky decreased daytime solo
accidents by 27% is suspicious on its face. If that doesn't raise an
eye-brow, you don't have eye-brows.

I think, that as a lawyer, you likely understand that the fact that the
DRL is powered by a magnetic dynamo is irrelevant in terms of its
effectiveness.

The "magnetic dynamo" is one or two isolated magnets attached to the
spokes and passing a coil built into the light. You get either one or
two tiny pulses of electricity per wheel revolution. It's like a 4th
grade science fair project.

It can't possibly put out anywhere near the power of a real bike dynamo.
Yet you're the person who has spent years claiming that real bike
dynamos are completely insufficient.

In the earliest reports I was able to find on the study the results
were stated to have been " The experiment resulted in a change in the
law in Denmark, flashing lights are now legal."

A study that, depending on where reported, varies by some 32% in
effectiveness, does not seem like a very authoritative source.

But accuracy aside both of the reports quoted above stated that
"Furthermore, 85%* of our induction light users have expressed to have
felt safer whilst riding in traffic.", which I believe is true, and is
exactly what the two most prominent California DRL adherents are
saying.... that with bright DRL's they feel safer.

Unfortunately feeling safe and being safe are not necessarily based on
the same conditions.

Only salesmen (including guerilla marketing expert dimwits) would call a 5
cd front light DRL. Present DRL on Danish streets is described in UNECE
Regulation 87: more than a factor 100 more intense at 0V-0H.

To be fair, quoting Reelight's FAQ, some of their cr*p might have gotten a
bit brighter:
quote
Hub Lights with flash (SL100) emits 29 cd from the front light and 10 from
the rear light.

Hub Lights with ReePower (SL120) emits approx. 24 cd from the front light
and approx. 8 from the rear light.
/quote
The table doesn't even address vertical angle. I guess the cars are really
low to the ground in Denmark.

(It's those crushing Socialist taxes!)

Not only the cars are low, but Sun is low on the horizon. Luckily, if you
don't mind a bit of extra weight on your bike, Joerg will help you build an
extra strong flasher for your safety:
https://en.wikipedia.org/wiki/Nuclear_pulse_propulsion